If you can exclude the ppl that say slurs, the ppl that say slurs can do the same, ending up in slurland, were they get worse and worse until they go to the street and kill someone.
It is not that we must allow people to say slurs, is that it is better for those people to say slurs in a public multicultural site, so that good people can essentially social pressure the slurers into simply not saying slurs. This was possible with centralized social networks, but with decentralization is not possible as the nature of decentralization means that those kind of people now can create their own bubbles of hate instead of having to behave to be in the public spaces.
This doesn't respect the power of the radicalization pipeline and let's others escape accountability for their part such as avoiding conflict when their friend says a racial slur or joins an incel forum rather than providing a less extreme take.
Small price to pay for a functional democracy comprised of unprecedented individual liberties.
But since some of the least-creatively-programmed amongst us want to use the "n-word" as an example (how surprising,) let's.
When and who get to decide which buzzword becomes a slur today? Tomorrow?
There are black Americans who prefer the word "negro," instead of the latest white-savior siccophant, acting as a virtue-signaling intellectually degrading euphemism.
Basketball Americans do not need your saving, thank you Mr Mayonnaise Man.